/Engine/Source/Runtime/Engine/Classes/Engine/GameInstance.h
Called to initialize the game instance for PIE instances of the game
virtual [FGameInstancePIEResult](API\Runtime\Engine\Engine\FGameInstancePIEResult) InitializeForPlayInEditor ( int32 PIEInstanceIndex, const [FGameInstancePIEParameters](API\Runtime\Engine\Engine\FGameInstancePIEParameters) & Params )